The majority of race based sports involve one coach, multiple athletes, and multiple crucial performance metrics per athlete. This generally creates the inevitable situation where there are too many performance metrics and too many athletes for a coach to focus on simultaneously. This results in the coach focusing on few athletes at a time or only one or two metrics at a time, with all of the other information being lost. Not only does this limit the amount of real time action that the coach can perform during a workout, but it also removes any possibility of long term tracking of these performance metrics over the athlete's season. Naturally, if the coach cannot even calculate all of the metrics, it is impossible for them to record them. Competitive swimming is one example of these sports.
Competitive swimming, whether it is in a pool or in open water, is a sport driven by numbers and statistics. Many people do not realize it, but coaches and swimmers are constantly counting or calculating metrics while they are training. Coaches on deck do their best to track metrics, calculate metrics and act on over a dozen metrics at different times while also watching each swimmer in turn to find general technique problems. This process of calculating metrics is very time consuming within the limited practice times and can be inaccurate when a large number of athletes are in the water. As recording metrics is generally not practical or even impossible, there is no way for a coach or athlete to accurately track their progress over the course of a season or to note negative trends as they arise.
If the coach wants a swimmer to change something mid-swim he/she has to catch the swimmer's attention either by waving or yelling, then the swimmer has to stop mid-swim to listen, and then start again.
Team swimmers are not the only ones faced with challenges. The casual lane swimmer, non-team triathlete, or anyone swimming on their own face these same issues of trying to keep track of these and other swimming metrics but do not have the luxury of having a coach to help keep track of this data and fix technical issues. On top of this, a solo swimmer faces the problem of general boredom while swimming without a team.
Existing devices are intrusive to the swimmer such as a wrist/ankle band or chest strap which are less than ideal in a sport where minimizing resistance in the water may be important and directly impacts performance as well as the swimmer's “feel” in the water. Other devices require user interaction using an array of buttons. This required physical interaction further impedes the swimmer's experience during their workout.